Fix shellcheck errors

Change-Id: I71f8e41f73ce998fe351bdabbdc291f1aa006dcf
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/vpnor/obmc-vpnor-util b/vpnor/obmc-vpnor-util
index e69390e..b02bfd8 100644
--- a/vpnor/obmc-vpnor-util
+++ b/vpnor/obmc-vpnor-util
@@ -70,7 +70,7 @@
   lowestPriority=255
   for element in "${array[@]}"; do
     #Remove the PNOR_RO_PREFIX from the path to get version ID.
-    versionId="${element#${PNOR_RO_PREFIX}}"
+    versionId="${element#"${PNOR_RO_PREFIX}"}"
 
     # Get the priority of active versions from persistence files.
     if [[ -f "${PERSISTENCE_PATH}${versionId}" ]]; then